[Taxacom] Integrative taxonomy, bacterial phyla, and a Two Domain classification

[Kenneth Kinman]

 Hi All, 
        I would definitely agree with Richard that
greater use of subspecies would be helpful when they are appropriate,
especially when they are geographically distinct, but not very distinct
morphologically or molecularly.   And that would also help solve the
problem which Wolfgang brought up (those sneaky taxonomic vandals).
    
       In my opinion, the best use of "candidate" taxa has
been with higher level bacterial taxa, especially large numbers of
candidate phyla (divisions). I was a little concerned to see that
Candidate Phylum TG1 was formally named so soon (in 2009) as Phylum
Elusimicrobia (see below for warnings about pendulum swings).
         
        On the other hand, I had to rant for years to finally
get Family Synergistaceae and Order Synergistales recognized as
distinct. And when they finally did, they went overboard and even named
a totally separate Phylum Synergistetes. Therefore, be careful what you
wish for, because you may not only get what you wished for, but a
pendulum swing that goes too far the other way.  Too much, too late!!!
       
       Anyway, a lot of candidate phyla proposed for bacteria
probably don't deserve phylum status and will become part of established
phyla.  Even I realized the distinctiveness of the bacteria in my new
Class Verrucomicrobea (in my 1994 classification), but then somebody had
to raise it to Phylum Verrucomicrobia.  Since then, it got lumped back
(with Lentisphaerae, also raised to phylum level at one point) with
Chlamydiae.  Who knows what other Classes might get lumped into Phylum
Chlamydiae.       
      Too many phyla in Kingdom Eubacteria just repeats the old pattern
of too many phyla in Kingdom Metazoa.  Need to learn from past mistakes
to avoid making the same mistakes in another taxon.  The biggest mistake
of all was raising Kingdom Eubacteria to Domain Bacteria in 1990.  After
20 years, you would think the Three Domain classification would be
dumped on the trash heap, but being more recent than the Five Kingdom
classification, I guess the novelty still hasn't worn off.  A
Six-Kingdom classification (in two Domains, Prokaryota and Eukaryota)
might turn out to be the best compromise of all.      
                 ----------Ken Kinman